1. Field of the Invention
This invention relates to a manipulator, and particularly to a manipulator suitable for use in conjunction with medical imaging devices.
2. Description of the Related Art
Medical biopsies and other medical procedures are frequently performed in conjunction with imaging equipment, such as CT (computer tomography) equipment, conventional x-ray equipment, magnetic resonance imaging equipment, or other imaging equipment. In a biopsy performed with such imaging equipment, a biopsy needle is inserted into a patient""s body while the patient is outside the imaging equipment, the patient is placed inside the imaging equipment, and then an image is taken of the patient""s body with the imaging equipment to determine the location of the biopsy needle with respect to the region where the biopsy is to be performed. It is frequently difficult or unsafe for a human operator to adjust the position of the biopsy needle while an image of the patient""s body is being taken due to the small amount of space between the interior of the imaging equipment and the patient""s body, due to the undesirability of the operator being exposed to radiation from the imaging equipment, or due to the operator interfering with imaging if standing close enough to the patient to manipulate the biopsy needle. Therefore, each time the position of the biopsy needle needs to be adjusted, the patient must be withdrawn from the imaging equipment, and after the position of the biopsy needle has been changed, the patient is reintroduced into the imaging equipment and the location of the biopsy needle is again checked. Since the operator cannot view the position of the biopsy needle within the patient""s body as he adjusts the position, the process of positioning the biopsy needle is essentially one of trial and error and so can be time-consuming and imprecise. The same problems occur with procedures other than biopsies, such as during the insertion of catheters.
The present invention provides a manipulator capable of inserting a needle or other object into a patient""s body for diagnostic or therapeutic purposes and adjusting the position of the needle within the patient""s body while imaging of the patient""s body and the needle or other object is being carried out.
The present invention also provides an input device for use in controlling such a manipulator.
The present invention further provides an apparatus for inserting an object into a patient""s body.
The present invention additionally provides a biopsy needle which can be assembled from a plurality of needle sections. The present invention still further provides methods for performing medical procedures.
According to one form of the present invention, a manipulator is capable of manipulating a medical tool with respect to a patient with at least one degree of freedom and preferably with multiple degrees of freedom.
In preferred embodiments, the tool can be manipulated with five degrees of freedom.
In preferred embodiments, the manipulator may be sufficiently small to readily fit into the space within an imaging device between a patient""s body and an interior wall of the imaging device, but the manipulator can also be used to manipulate a medical tool with respect to a patient who has been removed from an imaging device.
A manipulator according to the present invention can be used with any type of imaging equipment, including computer tomography machines, magnetic resonance imaging machines, conventional x-ray machines, fluoroscopy systems, and ultrasonic imaging systems. However, it can also be used in applications not involving imaging. The image may be displayed for the operator in any convenient manner, such as on a CRT or other type of electronic display, or in the form of a printed image on a sheet.
In one mode of operation, the manipulator introduces a medical tool into a field of view of the imaging device while imaging is taking place, so that an operator can view an actual image of the tool. In another mode of operation, the manipulator introduces a medical tool into a region of the patient""s body after imaging of the region has taken place, and a virtual image of the medical tool is superimposed on an actual image of the region to indicate to the operator the location of the medical tool with respect to the region.
A manipulator according to the present invention can be used to manipulate a wide variety of medical tools both for therapeutic and diagnostic purposes, a few examples of which are biopsy needles, biopsy guns, various probes including cryo probes and radio frequency probes, lasers, laser hyperthermia devices, cameras, and needles for administering various substances, such as biotherapeutic agents, alcohol, or radioactive pellets, to the interior of a patient""s body. In addition to tools which are inserted into a patient""s body, it can be used to manipulate tools which are normally utilized on a patient""s skin.
A manipulator according to the present invention may be operated in a master-slave mode, a fully robotic mode, or a semi-robotic mode in which some of the motions of the manipulator are controlled by input commands from an operator and other motions are controlled automatically.
The manipulator can be controlled by various input devices. According to one form of the invention in which the manipulator operates in a mater-slave mode, the manipulator can be controlled by a haptic input device which provides force feedback to the hand of the operator of the input device. The force feedback may be indicative of the resistance to movement encountered by the medical tool. The force feedback may also be controlled so as to assist the operator in more safely guiding the medical tool. For example, the force feedback can be controlled so as to inhibit the operator from moving the tool to the vicinity of delicate objects within the patient""s body.
A manipulator according to the present invention is particularly suitable for manipulating needles, such as biopsy needles. According to one form of the present invention, a needle for use with a manipulator can be assembled from a plurality of needle sections. The needle may be assembled while imaging of a patient is taking place immediately before the needle is inserted into the patient, and the needle may be disassembled into the individual needle sections as it is being withdrawn from the patient. The ability to assembly a needle from a plurality of needle sections makes the insertion of an elongated needle into a patient much easier and enables the manipulator to be introduced into crowded spaces which could not be accessed with a one-piece needle of the same length.
A manipulator according to the present invention enables a medical tool to be manipulated inside tight spaces in which it would be difficult or impossible for a human operator to position a tool or in environments which would be unsafe for a human operator. In particular, the manipulator can manipulate a medical tool with respect to a patient inside imaging equipment, which tend to have very small clearance surrounding a patient""s body during imaging. Therefore, the manipulator enables the position of a medical tool with respect to a patient to be adjusted while imaging is taking place and makes it unnecessary to remove the patient from the imaging equipment each time the position of the tool needs to be adjusted. For this reason, the medical tool can be positioned quickly and accurately, enabling a medical procedure to be performed with the tool efficiently and economically with less stress on the patient. The ability of the tool to be rapidly positioned is particularly advantageous when the tool is being positioned in or near the patient""s chest and the patient is holding his breath.
The manipulator can also reduce the fatigue experienced by a human operator, since it is unnecessary for the operator to physically support the medical tool during manipulation. The operator can let go of the manipulator while performing other tasks without the medical tool undergoing movement. Thus, the positional stability of the medical tool can be improved compared to when it is supported by hand. The ability of the operator to perform other tasks while the medical tool is supported by the manipulator can increase work efficiency and enable him to complete imaging more rapidly.
Furthermore, the manipulator can enhance the dexterity of the operator, i.e., it can enable him to manipulate a medical tool with greater dexterity than he could if directly handling the tool in his hands. For example, the manipulator can scale up or down the magnitudes of the operator""s hand motions or the forces he applies, it can eliminate the effects of tremor in his hands, and it can help him to guide the tool along a path avoiding delicate regions of the patient""s body.